1. Field of the Invention
The present invention relates to edge extrusions which are mounted on the top shell and bottom shell of a plastic case, and more particularly to edge extrusions to which casing hardware is attached and secured by crimping.
2. Description of the Prior Art
Presently cases are used to transport equipment from location to another. At its destination, the equipment is removed for use. The standard case is that of a "Clam Shell" design and has a top shell and a bottom shell. The case also has a pair of edge extrusions, one of which has a male edge and the other of which has a female edge, which are mounted on the peripheral rims of the top and bottom shells. The case further has a rubber gasket which is adapted to be placed between the male and female edges of the edge extrusions so that the case may be sealed.
The edge extrusions are generally formed from aluminum and when they are coupled together they formed an H-shaped member in a cross-sectional view. The peripheral rim of each shell is inserted into the space between the vertical portions of the H-shaped member and is secured thereto by epoxy. Once the edge extrusions are secured to the peripheral rims of the top and bottom shells casing hardware may be attached to the edge extrusions.
The casing hardward includes hinges, non-separable and slip hinges, locks, handles and clamps assemblies. In the prior art there are many methods of attaching and securing the casing hardware to the edge extrusions, but all these methods have drawbacks when they are used on a case which must not only be reusable, but also air-tight. Presently the preferred method of attaching and securing casing hardware to the edge extrusions consists of riveting the base of the casing hardware to the edge extrusion. The riveting produces a very secure joining of the base of the casing hardware and the edge extrusion, but the riveting also produces a hole in the sidewall of the shell thereby creating a leak in the case. Another problem arises when the casing hardware becomes damaged and must be replaced in order to reuse the case. If the casing hardware must be replaced in the field, it may be difficult to find a riveting machine. Furthermore, even if a riveting machine is available, it will create another set of holes in order to mount and secure the base of the casing hardware.
Another method of attaching and securing casing hardware to the edge extrusions consists of epoxying the base of the casing hardware to the edge extrusion. The epoxying produces a very secure joining of the base of the casing hardware to the edge extrusion. The epoxying produces a very secure joining of the base of casing hardware and the edge extrusion and it does not create a leak in the case. The problem with epoxying is that when the casing hardware becomes damaged and must be replaced, it is very difficult to remove the damaged casing hardware in order to replace it.
Reference to Environmental Container Systems' Standard Case Catalog provides one with a good example of casing hardware and edge extrusions which may be joined by riveting. Attention is also called to the smooth interior surface of vertical portions of the H-shaped member. The smooth interior surface is coupled to the sidewall of the shell by epoxy, but in some applications a more secure joining of the edge extrusion to the shell is desired. The only way to make a more secure joining is to rivet the edge extrusion to the shell, but riveting creates a leak in the case.
Reference to Hardigg Industries' Reusable Container Catalog provides one with a good example of an alternative to the use of edge extrusions. The Hardigg Industries' Catalog shows a double wall configuration at the case parting line. The casing hardware is attached to the double wall of the case by either rivets or epoxy. The double wall is molded into a male member and a female member and is sealed by a rubber gasket.
Reference to Skydyne's Catalog provides one with several examples of the various shapes that these cases may take. In all of these cases the edge extrusions extend completely around the peripheral rims of the top and bottom shells. These shells are generally formed out of plastic materials or fiberglass.
Reference to Zero Manufacturing Co.'s Deep Drawn Military Case Catalog provides one with a good example of an aluminum case shell to which casing hardware is attached and secured by rivets. The closure shown in this catalog is similar to the closure taught in U.S. Pat. No. 3,817,419, entitled Latch to Secure a Closure on a Container, issued to Jens L. Moller and Herbert S. Ruekberg on June 18, 1974. U.S. Pat. No. 3,817,419 teaches a latch mechanism carried by the peripheral skirt of a container closure.